1. Field of the Invention
Aspects of the present invention relate in general to an array type inkjet printer system and a controlling method thereof. More specifically, aspects of the present invention relate to an array type inkjet printer system capable of preventing excessive power consumption and a controlling method thereof.
2. Description of the Related Art
Generally, an inkjet printer sprays miniscule droplets of ink from tiny nozzles at a recording medium such as a sheet of paper or film, in response to a control signal.
According to the print head driving method, inkjet printers may be classified into array type inkjet printers and print head driving type inkjet printers. In the print head driving inkjet printer, a plurality of nozzles are arranged on the print head in the vertical scan direction, and the printer prints one line at a time as the print head moves in the horizontal scan direction. On the other hand, in the array type printer, a plurality of nozzles are arranged in the horizontal scan direction of the print head so that it prints each line in the vertical scan direction, and the print head moves only in the vertical scan direction.
The array type inkjet printer head is provided with a nozzle plate having a plurality of nozzles formed therein. The array type inkjet printer head may have several thousands of nozzles according to the resolution or the design used. The energy consumption of an array type inkjet printer have a large number of nozzles can be considerable. For example, suppose that 1,200 droplets are to be formed in each line. Since a color printer supports four colors CMYK (cyan, magenta, yellow and key (black)), a total of 4,800 nozzles (1,200×4=4,800) must be formed in the print head. Although there are slight differences among printers, about 2 μJ of energy is usually required to operate one nozzle. If a line is printed at a frequency of 20 kHz, the power capacity required for printing a line is as follows:Power capacity=4,800×2 μJ/( 1/20,000)=192 W.
This power capacity is a total amount of power required for printing a line completely, provided that the nozzles for each of four colors are all operated at the frequency of 20 kHz. Here, four colors indicate CMYK colors, i.e., cyan, magenta, yellow, and key (black). Since a black color is typically obtained by mixing the other three colors, two of CMY colors are usually mixed to obtain desired colors. Thus, the average number of nozzles used is 2.1, and the power capacity required therefor is as follows:Average power capacity required=192 W×(2.¼)=99.96 W.
In other words, the related art inkjet printer requires quite a lot of power, 99.96 W, for printing one line. Needless to say, a large size power supply unit must be installed in the printer to supply such a large amount of power, and this increases the cost overall.
Accordingly, there is a need to develop a method of reducing power consumption for array type inkjet printing.